September 30, 2005
Anatomy of a Transmission: Oil Flow in the Pump-PR-Converter-Cooler Lube Circuits
Gregg Nader
In ZF6HP21/28/34 (Generation 2) units, the variable force solenoids control clutch apply/release, torque converter clutch apply/release and line pressure. The solenoid pressure regulator valve insures proper flow volume and pressure to the solenoids during hot conditions and low pressure operation. Low feed pressure at idle can create delayed engagement or wrong gear starts. This valve also limits the maximum pressure to all the solenoids. Excessive solenoid feed pressure can flood the solenoids causing gear ratio codes, harsh up/downshifts and excessive line pressure. Sonnax oversized solenoid pressure regulator valve kit 95740-64K restores proper solenoid function.
• Kit fits either M-shift or E-shift valve bodies
• Hardcoat anodized aluminum valve combats premature wear
• Matching spring reproduces OE function with the oversized valve
Kit is NOT compatible with ZF6HP19/26/32 (Gen.1) units. To differentiate between Gen. 1 and Gen. 2 valve bodies, see ZF Identification Guide.
F-95740-TL17 can also be used to install ZF6HP21/28/34 (Gen. 1) Sonnax oversized solenoid pressure regulator valve kit 95740-17K.
Sonnax valve body layouts provide a detailed overview of individual units making it quick and easy to determine what’s available for the specific valve body you’re working on. See all Sonnax valve body layouts.
September 30, 2005
Gregg Nader
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